Fire extinguishing grenade



March 9, 1937. G. FlNzl FIRE EXTINGUISHING GRENADE 2 Sheets-Sheet l Filed April 6, 1935 March 9,1937. G. FIN-2| 2,073,416

F'RE EXTINGUISHING GRENADE 'Filed April e, 1935 2 sheets-sheet 2 Patented Mar. 9, 1937 UNITED STATES FIRE EXTINGUISHING GRENADE Gino Finzi, Rome, Italy l Application April` 6, 1935, Serial No. 15,125

, In Italy March 18, 1935 Claims. (Cl. 169-28) The present invention-relates to fire extinguishing grenades which Iare designed to be' thrown, manually or otherwise, onto a fire, whereupon the bursting, of an explosive charge, generally 5 centrally located in the grenade, generates an internal pressure which breaks the container and sprays the extinguishing charge, consisting either of solid substances preferably inthe form of powders, or of liquids, around the neighboring 1() Vicinity.

One of the disadvantages of the grenades previously n use is the fragility of their casings or containers; a fragility which has been'necessary to their proper operation, but which frequently 1,3 results in the casing, when it falls on the fire,

becoming impaired or partially broken. The internal pressure developed by the delagration of the bursting charge naturally follows a path of least resistance so that if the casing has been 20 weakened in any spot, the extinguishing effect is likewise weakened.'

The inconvenience is still greater when the extinguishing agent is a liquid which can escape through fractures before the operation of the 25 grenade.

To prevent this possibility of damage to the grenade, it has previously been suggested to protect the container with external adjacent layers of a thick substance, for instance strong paste- 30 board, but this expedient has proved undesirable in that the reinforcement servesas an obstacle to the scattering of the extinguishing charge, so

that a larger explosive charge must be used, as a' result of which the handling and throwing of 35 the grenade is dangerous.

The present invention is directed to an extinguishngf grenade which differs from the prior art grenades, and which avoids the aforementioned disadvantages, which ensures the safety 40 of its handlers and which ensures the greatest certainty of its operation and its extinguishing eiciency. My grenade is provided with a bursting charge contained in a spherical or spheroidalshaped cartridge i. e. an approximately bulbous 45 shape, having previously arranged rupture lines, saidcartridge being located at the centre of the grenade, and being tightly fitted on the usual internal, axial, tubular rod of the conventional grenade, the usual fuse being arranged within said 50 hollow rod and communicating with said bursting charge thro-ugh convenient vents provided in the tubular rod. Said tubular rod, which serves as a supporting armature for the grenade, is formed of a material capable of mechanically resisting 55 all the strains the rod is exposed to during all the tinguishing effect.

operations of shaping, charging and mounting the grenade; and at the same timev the rod constitutes an absolute protection for -the fuse con- -tained in the rod, the proper operation of this fuse thus being ensured for a long time after the construction of the grenade.

A spherical or spheroidal-shaped cartridge for the bursting charge has been chosen instead of a cylindrical cartridge because a container of cylindrical shape has walls which present too great a range of resistance to the deagration with the'result that there are created a plurality of zones between which zones there is a varying intensity with which the extinguishing charge is sprayed, so that there is a non-homogeneous ex- The axial armature tube .of the grenade, owing to its central location as regards the bursting charge, is subjected to oppositely directed pressure which balance each other in every direction and which prevent the projection of the charge. The ends of the axial armature tube are provided with concave or convex disc-shaped members of a material which is neither metallic nor liable to splinter, such for example as cardboard, papier mache and the like, these members keeping the tube in place, and completing and closing the casing or container of the grenade. The casing preferably consists of a thin, light, non-splinterable moistureproof material, which has been provided with numerous previously arranged rupture lines., whereby, when A the grenade is fractured, homogeneous scattering of the extinguishing charge is secured in all directions from the 'centre of the grenade toward the exterior, under the impelling action of the pressure'developed by the bursting internal explosive charge.

That part of the priming fuse which projects out ofthe container through the axial tubular armature rod of the grenade is protected by a tight case of a moisture-prooi material, which, being highly inflammable at the ambient temperature (or temperature of dark heat) or/when subjected to the ame itself, is soon ignited, the ignition being immediately extended to the fuse of the bursting charge. This case, for certain purposes, may be provided with lament-like extensions of variable length so that the ignition of the fuse may be quickened when desired.

The container of the grenade may be a polyedron of any desired shape, and may be pro'- vided with a shaft, handle, or shackle for being hurled or suspended. Because of the fragility of the container of the grenade, with its previously arranged rupture lines (a fragility `which stance.

is necessary for the proper operation of the grenade) an external basket protecting against shock has been provided, this basket being disposed at a certain distance from the container and consisting of a network formed with wide meshes composed of protecting rod-like elements connected at the ends, and having supporting hoods serving as a base, the network also being provided at the extremities of the internal tubular rod of the grenade. The network is made of a light, non-metallic material not likely to splinter, such for example as rubber, paper or cardboard hardened in any desired manner, or a textile material impregnated with suitable plastic masses. 'Ihis material may also be fixed to other pointsof the containers surface, forming curv'ed, elastic and deformable elements constituting a safe shock-absorbing device protecting the container should the grenade be dropped accidentally. The hoods preferably are provided with openings for the free passagel of the extensions of the inamrnable case of the bursting charge. The rod-like elements of the said network, due to their distance from the container and their convenient reduced section, interpose no obstacle to the homogeneous scattering of the extinguishing charge. In addition to the fuse already mentioned, a second fuse may be provided in order to ensure even more the proper functioning of the grenade. The second fuse may be of desired type, and preferably is associated with a time control device, said second fuse with its corresponding time controlling device always being arranged coaxially with the first fuse, but at the other end of the central tubular rod.

This sort of friction ignition control demands a design of the fulminating cap such that suilicient resistance is offered to support the tension (several kg.) necessary to unwind at certain speed the friction spiral on the fulminating sub- This resistance is not presented when the fulminating cap is located on exible` materials, for instance on the end of fuse tubes made of cardboard or celluloid which, in turn, bear on rigid elements, whereby there is the possibility that the fulminating cap may recede from the-match just an instance before ignition, so that the functioning of the grenade fails. My arrangement, on the contrary, of the control in the only resistant member of the grenade, i. e. in the armature axial central rod, ensures the immobility of the parts and consequently their invariable functioning, as in the case of a fire arm.

By my invention itis possible to construct a grenade of any desired shape, which grenade has a handle, and which is provided with two fuses for the bursting charge, one of which is heatcontrolled, and the other of which is time-controlled by means such as a laniard to be pulled with a jerk. Both fuses are always arranged longation of said rod, this shaft preferably being perforated longitudinally in order to allow the passage of the laniard of the time fuse,

which is to be pulled at the moment of ignition,`

the laniard being shown as terminating in a ring or hook.

Other grenades may be without shafts but with the same fuses as above mentioned, either one or both, the shaft being replaced by a hood having openings the hood preferably being constructed of a material not likely to splinter. The wood serves to fix the network and the pulling device for the time fuse, and it may also be utilized to allow the passage of the eventual filament-like extensions in the instance where the fuse is of the thermal type. The grenades will be provided with a launching and suspension handle or shackle made of a suitable flexible light material, the said handle or lshackle being connected in any desired manner to either or both of the containerv and the protecting network of the grenade. The handle or shackle may also be formed of one or more elements of the protecting network or basket and projections therefrom.

In order to illustrate the advantages of the grenade according to my invention both when providedwith a shaft or flexible shackle and when there is no shaft, the grenade in the lastmentioned case always being equipped with the protecting network, two modifications will be described in connection with the accompanying drawings in which the same parts are indicated by the lSame reference numerals.

In the drawings, Fig. 1 is an axial section of the extinguishing grenade, having a manoeuvring shaft provided with two fuses, one thermal, the other time-controlled, the latter being of the type provided with a laniard to be pulled with a jerk immediately before the grenade is thrown into the fire. The grenade is illustrated without the protecting network.

Fig. 2 is an axial section of an extinguishing grenade which has no shaft and which is particularly fitted for launching, it being provided with a flexible launching or suspension shackle, with two fuses for the bursting charge, one with thermal control and the other with time control of the type having a laniard to be pulled with a jerk when the grenade is launched; both control devices being coaxially arranged in the same tube in a manner similar to that illustrated in Fig. 1.

In Fig. 1 the supporting axle or armature of the grenade consists of a tubular rod I of convenient material, the upper end 2 of which is externally threaded to cooperate with a double nut 3 which fixes in position the cover 4, the latter being made of a non-metallic, non-splinterable material, and serving to close the top of the container 5 of the grenade, the said container being provided with previously arranged lines of rupture, not illustrated. The lower end of the rod I is flared as at.6 and is threaded at 1. The flared end 6 has a flange 8`\- supporting the bottom cover 9, and 'this ange bears, vby means of its outer surface, and preferably through the intermediary, of a washer Ill, on the longitudinally bored shaft H made of wood or other suitable material and which isthread-ed or otherwise secured to a perforated connection l2 of convenient material,

which connection l2 is threaded or otherwise Secured to a central bore in the flaring end 6 of Athe tubular rod I, acomposite unit thus being obtained which can be easily assembled and taken to pieces, so that when the grenade is already charged and is ready for use, there' can be installed the time-controlled fuse of the type having a laniard'to be pulled when the grenade is aboutto be thrown, and which operates on a fulminating friction cap. I3, the friction spiral I4 ofwhich extends through the connection I2 and shaft II,

J to a thread I5 which terminates in the manoeuvring ring I6. When the detonating cap I3, with its friction-spiral Il extending to cord I5 of the friction time fuse, is arranged in the tube I, it is in immediate contact with the safety match I1, which is of the slow-combustion type. so that when it is ignited by the friction cap I3, an appreciable time isrequired for transmitting the ignition to the fuse match I8, the deflagration of which, when it reaches the vents I3, ignites the bursting charge contained in the cartridge 2I,

which cartridge, which is spherical or of any other desired'shape, is so fixed on the tubular 20 rod I that the vents I9 are centrally arranged.

The 'fusing match I 8, whose lower end is in contact with the safety match I1, extends through thetubular rod I beyond the vents I9, the end 2 of the rod IV projecting beyond the container 5,

this end 2 being externally threaded, and the match I8 terminating in an end 22 which pro- Y jects beyond the end 2, and which is completely covered with a tight case 23 preferably formed of a cellulose derivative, and which is moistureproof, with a very low point of iniammability. This case 23 is shown as provided inits external upper part with priming filaments 2l of the same material, with very low point of inammability, projectingexteriorly through wide openings 25 friction spiral I4, the friction detonating lcap I 34 and the safety match I1 of previously arranged duration of slow combustion. Should the extinguishing grenade -be thrown or' launched onto the seat of fire, the protecting network or basket (not illustrated'in the drawings) is first to be fixed,-

on one side to the h ood 28, andon theA other side to the manoeuvring shaft, for example by means of a convenient fixing ring-shaped member (not Shown).-

The operation ofthe above-described extinguishing grenade is very simple and very safe.

By holding the grenade by .means of shaft II,

the ring I 6 of cord I5 is pulled, thus causing' the sospiral Il to be unwound, `'Ihe friction causedl by the unwinding Vof this spiral produces ther detonation of cap I3, thereby causing the slow combustion of match I1, for a previously arranged time interval, the grenade then being placed in any desired manner on the seat of ire, the filaments 2l extending out of the openings 25 of the protecting hood 26 thereafter being ignited either by the heat of the fire or'by contact with-the flames, so that the fuse match I8 is ignited, as a result ofwhich, the fuse, ignited at both ends, transmits the `iame through the vents I9 of the tubular rod I to'the bursting charge 20, which upon deflagrating, bursts the container 5 with its previously arranged rupture lines, and the lyextinguishing substance is scattered homogenea,o7s,41e y u 3 ously over the neighborhood of fire so that the latter is speedily quenched.

Fig. 2 shows a typical extinguishing 'grenade adapted to be launched without the use of a shaft, and which grenade is provided with network or 5 #protecting basket comprising rod-like elements 21 made of non-splinterable flexible material, the container or casi'ng being illustrated as spherical in shape, although of course it may be of. any other desired form, the casing in any ev'ent being 10 provided with previously arranged rupture lines 28, the internal amature consisting of the same tubular rod I as in Fig. 1, constructed of suitable material, and with the same cartridge 2| containing the bursting charge 20, similar to the grenade 15 illustrated. in Fig 1. The -internally-threaded, flaring end 6 of the tubular rod I`, which according to Fig. 1 is flush with the perforated shaft of wood or other material, is provided in this case with a small', bored connection 29 'for the passage. 20 of the pull cord I5 of the detonating friction cap' I3 of the time fuse, the wood shaft being substituted by a .protecting hood 26a similar to hood 26 protecting the other end zone of the grenade, the protecting network or 'basket' bearing on-said 25 hoods and consisting of the rod-like elements 21 of flexible, non-splinterable material, said protecting device serving as a shock absorber. The ring I6 projects through the openings 24 of one of said hoods, preferably the hood 26a; the ring, 30 when pulled, tightening the thread I5 and caus-v ing the spiral I4 of the detonating cap I3 to be unwound, so that the time-fuse controlling device functions at the instant the ygrenade V-is launched, while through' the openings of 'the 35 .other hood 26 the igniting filaments of the thermal fuse project, said filaments being ignited when the grenade falls 'on the seat of fire or inV proximity thereto.

For the purpose of launching, this'grenade is 40 provided with a shackley 30 of textile material having a yoke 3i extending all around the gre; l nade in a plane perpendicular to the 'tubular rod, said shackle also serving for fixing to the surface of the container the protecting rod-like elements 45 21 of the protecting basket, so that the elements 21 are spring-like and curved, constituting cer. tain shock absorbers for protection, and cooperating together with the two hoods 26 and 26a to protect Athe container of the grenade against "n damage when the grenade falls. I

The operationof said grenade is similar to that of the' grenade illustrated in Fig. 1'.

It is obvious that besides thej two examples of 55 the invention above disclosed and illustrated in Acartridge containing anr explosive charge tightly disposed about said rod, said tubular rod being constructed and arranged to constitute the interv nal' axial supporting armature; of the whroleas- 70 semblage of the extinguishing grenade, igniting fuses for Athe exploding charge coaxially arranged within said rod, an actuating. device for one'of said fuses also disposed coaxially within said rod,

said fuses cooperatively arranged tl'lerewith coaxial with said rod.

2. Fire extinguishing grenade according to claim 1, in which said tubular rod is provided at about its midpoint with radially disposed vents extending from one side to the other, so that when one of said fuses burns its ame is-propagated through the vents to the explosive charge whereby the latter is exploded and the extinguishing charge scattered about.

3. A fire extinguishing grenade comprising an approximately bulbous container or casing, a tubular rod constructed and arranged to constitute the internal axial supporting armature of the whole assemblage of the grenade, an explosive charge disposed in a cartridge mounted in annular manner tightly about said tubular rod near its midpoint, an extinguishing charge surrounding said cartridge, igniting fuses for the exploding charge coaxially arranged within said rod,

an actuating device for one of said fuses also coaxially disposed within. said rod and a second actuating device for the other of said fuses cooperatively arranged therewith coaxial with said rod, said rod being provided near its midpoint with vents defining a transverse passage through said rod and opening into said cartridge so that when one of the fuses burns, its flame is propagated through the vents to the explosive charge,

whereby the latter is exploded, so that the extinl guishing charge is scattered.

4. A fire extinguishing grenade comprising an approximately bulbous container or casing, an extinguishing charge therein, a tubular rod disposed along the major axis of said container,

disc-like members for completing the surface of said container and tightly closing the container to the exterior, means on both ends of the tubular rod for fixing and positioning said disc-like members thereon, a cartridge containing an explosive charge tightly disposed about the said tubular rod, said tubular rod constructed and arranged to constitute the internal axial supporting armature of the whole assemblage ofthe extinguishing grenade,` igniting fuses for the exploding charge coaxially arranged within said rod, an actuating device for oneof said fuses also 60 axial-supporting armature of the whole assemblage of the extinguishing grenade, igniting fuses for the exploding charge coaxially arranged within said rod, and a controlling device disposed at one end of said rod for the ignition of the fuse 65 and extending to the exterior through the bore of said connection.

6. A nre extinguishing grenade comprising an approximately bulbous container or casing, an extinguishing charge therein, a tubular rod,"a

70 cartridge containing an explosive charge tightly disposed about said tubular rod, said tubular rod constructed and arranged to constitute the internal axial supporting armature of the whole grenade assemblage, igniting fuses for the ex- ',-5 ploding `charge coaxially arranged within said rod, an actuating device for one of said fuses disposed at one end of said rod and operable from the exterior of said casing, one end of the other fuse projecting beyond said rod, a case of material of very low b urning point enclosing said last mentioned end, and lament-like extensions of varying length projecting from said case and capable of being ignited at temperatures as low as those prevailing in a dark red fire, and serving to produce the ignition of the fuse within said case.

7. A fire extinguishing grenade, comprising an approximately bulbous containei or casing, a tubular rod constructed and arranged to constitute the internal axial supporting armature of the whole assemblage of the grenade, a cartridge, tightly mounted about said rod near its midpoint, an explosive charge in said cartridge, said 'rod being provided near its midpoint with vents defining a transverse passage through said rod, and opening into said cartridge, fuses extending through said rod and juxtaposed adjacent said vent, one of which projects at one end of said rod and is of the thermal type, and the other of which projects at the other end of said rod and is of the safety type, with a previously iixed duration oi.' burning, an ignition controlling device having a friction detonating cap disposed in said rod in conjunction with said last-mentioned fuse, and a cord projecting from said rod for actuating said detonating cap, the-flame of the burning fuses being propagated through said vents to said charge, whereby the latter is exploded and the extinguishing charge scattered.

8. A fire extinguishing grenade' comprising an approximately bulbous container or casing, a tubular rod constructed and arranged to constitute the internal axial supporting armature of the whole assemblage of the grenade, an explosive nucleus charge disposed in a cartridge tightly mounted in annular manner about said tubular rod near its midpoint, both the container and the cartridge being provided with previously deter' mined lines of rupture in order to obtain the greatest uniformity in the scattering of the extinguishing charge, an extinguishing charge within said casing, and igniting fuses for the explosive charge disposed coaxially within said rod, an actuating device for'one of said fuses also disposed coaxially within said rod, and a second actuating device for the other of said fuses arranged cooperatively therewith and coaxial with .said rod. said rod being provided near its midpoint with vents dening a transverse passage through said rod and opening into said cartridge so that when one of said fuses burns, its fiame is propagated through the vents to the explosive charge, whereby the latter is exploded thus scattering the extinguishing charge.

9. A iireextinguishing grenade comprising an approximately bulbous container or casing, an extinguishing charge therein, a tubular rod, a cartridge containing an explosive charge tightly disposed about said rod, said tubular rod being constructed and arrangedvto constitute the internal axial supporting amature of theI entire grenade assemblage, igniting the fuses for the exploding charge coaxially arranged within said. rod, devices for igniting said fuses cooperatively associated with said fuses and said rod, a protecting cage having wide meshes encircling said container in spaced relation thereto, and shock absorbing supports for mounting said container in said cage.

10. A re extinguishing grenade comprising an approximatelyv bulbous container or casing. a

tubular rod constructed. and arranged to serve as the internal axial supporting member of the entire grenade assemblage, a cartridge containing an exploding charge tightly mounted in annular manner about said tubular rod near its midpoint, an extinguishing charge in said casing, igniting fuses for the exploding charge disposed coaxially 10 within said rod, actuatlngdevices cooperatively GINO FINE. 10 

